package main
import "fmt"

func main(){
  fmt.Printf("%d is even: is %t\n",16,even(16))
  fmt.Printf("%d is odd: is %t\n",17,odd(17))
  fmt.Printf("%d is odd: is %t\n",18,odd(18))
}
func even(nr int)bool{
  if nr == 0{
	return true
  }
  return odd(RevSign(nr)-1)
}
func odd(nr int)bool{
  if nr == 0{
	return false
  }
  return even(RevSign(nr)-1)
}
func RevSign(nr int)int{
  if nr <0{
	return -nr
  }
  return nr
}
